potassium tert-butylate in N,N-dimethyl-formamide T=-60°C; 2 h; further catalyst: KF;

1: KOtBu / dimethylformamide / 2 h / -60 °C / further catalyst: KF 2: 91 percent Chromat. / KOtBu / dimethylformamide / 0.25 h / -60 °C 3: 35 percent Chromat. / KOtBu / dimethylformamide / 1 h / -60 °C View Scheme

1: KOtBu / dimethylformamide / 2 h / -60 °C / further catalyst: KF 2: 20 percent Chromat. / dimethylformamide / 0.25 h / -60 °C View Scheme

1: KOtBu / dimethylformamide / 2 h / -60 °C / further catalyst: KF 2: 49 percent / O2 / KOtBu / dimethylformamide / 1) -60 deg C, 2) r. t., 4 h View Scheme